A solid-state light emitter (e.g., a light emitting diode (LED) or laser diode) typically emits a single wavelength of light, the intensity of which can be adjusted by adjusting (e.g., modulating) the emitter's drive current. To generate a light of varying color, or to generate a color of light that corresponds to something other than an emitter's single wavelength of light, two or more different-colored emitters may be positioned such that their emitted light mixes to form yet another color. In some cases, the light emitted by a plurality of different-colored emitters is mixed to form a steady-state color. For example, the light emitted by red, green and blue light emitters is often mixed to generate a white light (sometimes for the purpose of backlighting a display). In other cases, the light emitted by a plurality of different-colored emitters is mixed to generate a series of colors (sometimes for the purpose of generating a pixel of data for a dynamic display). This may be accomplished, for example, by varying the ratios of drive currents supplied to the different emitters.
In both of the above cases, it is typically desired that the light emitted by the different-colored emitters mix to form a uniform light of a different color. However, given that solid-state light emitters are more akin to point light sources than diffuse light sources, a thorough mixing of their light can be difficult to achieve.